I'll be using two G-38's in a new B-25 and want to have both a manual ignition cutoff as well as a transmitter-controlled cutoff. Since the engines have magnetos, for the transmitter-controlled cutoff I was thinking of a servo to switch, using a pushrod to actuate the switch. I'm sure some of you have already solved this problem, and I'd appreciate your input on how to accomplish this and what switch to use. Thanks, Lee

Hey Lee

Have you looked at these ? > http://www.smart-fly.com/Products/Ignition/ignition.htm

Why won't one simple switch to ground both magneto coils work equally well ???

I would recommend that you use an electronic switch.
SMart Fly and Electrodynamics both offer a solution for your needs

The two ignition devices might possibly try to form a ground loop through each other and neither one will work? They must be kept seperate.

You might get away with a DPST switch?

Enjoy,

Jim

Yeah I was thinking of them to but could not remember there site.
Could you post there web site please.
TIA

http://www.electrodynam.com

I've got the ElectroDynamics electronic switch on my Brison powered Edge and I don't see how it will work with a magneto engine. It cuts the power from the ignition battery to the engine via an optical connection to the receiver. Since the G-38 does not use an ignition battery, I don't see how any electronic switch that cuts ignition battery power will work. I believe he is going to need a servo to throw a microswitch or hook up a choke servo to kill it that way.

Thanks to all of you who have responded. I've already talked to Electrodynamics, and their system (and the SmartFly system) will only work with electronic modules, not magneto ignition. Yes, ground loop might be a problem, so I'd probably have to put a diode on one side to stop current flowing back through the open mechanical switch.

Maybe I'm making too big a deal out of this, but I thought that someone would have already solved this problem with magneto engines. This project is costly enough, and I don't want to spend more on the engines to have them converted to electronic ignition. This is really a safety issue, so if for some reason I lose one throttle servo during flight and that engine keeps running full bore, I'd like to be able to kill both engines and land dead stick. Asymmetric thrust on a B-25 wouldn't be much fun at all!

Perhaps the choke servo is the best way, but I'm still open for ideas.

Thanks, Lee

One switch to ground out two magnetos should not be a problem. If your worried about the ground loop, use a dpst switch.

No problem
http://www.electrodynam.com/
http://www.smart-fly.com/

I like the SuperRocker switch available from Madison Quality Products or Heliproz... lifetime guarantee (sp?). 16 Amp switch. I usually run 2 RX and have a choke servo on the oppsite RX from the throttle to give myself 3 ways to kill the motor.

i was wondering if you could use two of the great planes gas engine ignition kill switch,part# LXJ776 . they sell for $7.99 ea, from tower hobbies. the wiring harness has a hand off/on switch and a micro switch,you could install the two micro switches,one on each side of the servo you would use for a engine shutoff . you would shap the servo round arm with flat sides so that when the servo is activated the arm would pivit,contact the two micro switch arms compressing them to activate the switch and ground out the mags,shutting the engine down,i hope this is understood.yours truly,arnie..

as i have the fuji 32b engine,this is whut i am going to use,but as i only have one mag i will only use one.excuse the spelling.arnie...

I'm new to giant scale. I have a g-38 engine (magneto style) I'm not shure what year the engine is. I want to connect a kill switch but do not see any obvious points to connect to. Below the coil is only a amall tab w/ a black wire soldered to it, no other connections. Any help would be appreciated.

Greenhornet,

Simply extend the black wire and connect to a 'kill switch' suitably located on the model and ground the other end of the switch to your engine case. When the switch is open the engine will run and when closed the engine will shut down.